It has been proposed to monitor rupture discs so that an indication of rupture can be obtained. Rupture discs are frequently installed under relief valves to prevent pollution by leakage and to ensure correct operation when needed. Unfortunately, when a pressure surge results in a relief valve opening, the rupture disc below it is destroyed. After the valve recloses, it often leaks, with a resultant pollution problem, particularly in chemical plants and oil refineries. Also flow monitors can be used to detect, and indicate flow downstream of a valve which is supposed to be closed.
Various forms of monitor or indicator exist. One example is a light beam monitor in which flow interrupts the light beam, indicating rupture. Another form uses paddles which are deflected by flow such as through a ruptured disc. These paddles are damaged by sudden flows and need replacing. In other forms electrical paths are formed which are broken on flow of a fluid. Electrical feed members or items, are often supplied as part of a rupture disc assembly itself and is at least difficult to retrofit to existing installations.
The various forms of monitors or indicators suffer from one or more disadvantages. The actual installation can be expensive. The associated equipment, for example, the light beam monitor is expensive and requires some place to position the light producing and beam monitoring apparatus. Replacement can often be difficult and may require replacement of an entire unit, which is inefficient.
It is a principal object of the invention to provide an improved fluid flow monitor. It is a subsidiary object to provide paired annular coaxial electrically conductive supports one having a smaller external diameter and a larger internal diameter, than the other. It is a further subsidiary object to provide a floating ground to check for ground fault tripping of the monitor. It is a further subsidiary object to provide tabs projecting inward from the supports to mount connections thereon.